Apparatus for compressing finely divided solids



Aug. 25, 1959 1.. A. HAMPEL ET AL 2,900,664

APPARATUS FOR COMPRESSING FINELY DIVIDED SOLIDS Filed Sept. 1, 1955 3 22 I WMII I 9 s Inuuulmulliu I l lg, j lllm Egg nul llll l llll MINIMUM! I INVENTORS Lows A. HAMPEL By Mama-mm J1 Mar APPARATUS FOR COMPRESSING FINELY DIVIDED SOLIDS Louis A. Hampel and Waldemar J. Wick, Milwaukee,

Wis, assignors to Kolnrar Laboratories, Inc., Milwaukee, Wis, a corporation of Delaware This invention relates to apparatus for compressing finely divided solids and more particularly to an apparatus for compressing powderous material into cake form.

When compressing a finely divided material such as face powder or the like, provision is made during com- .pression for the escape of air entrapped within the powder. In the conventional type of compressing apparatus the air is permitted to escape during compression through a series of openings which are provided in one of the die members. The entrapped air, if not released, would form pockets of compressed air in the finished cake which would provide the cake with a relatively porous consistency and increase the chance of fracture or" the cake.

The present invention is directed to an apparatus for compressing finely divided material, such as powder, in which the air contained within the material can be quickly exhausted from the material and thereby substantially increase the speed of operation over that of the conventional compressing apparatus.

According to the invention the apparatus includes a porous metallic disc adapted to support the powder and which contains minute openings or pores through which air under pressure can pass. The disc rests on a lower die member and the upper surface of the disc which sup- States Patent ports the powder to be compressed is plated with chromium. The chromium plating provides a smooth surface which aids in the release of the compressed cake, and the chromium plating is characterized by the property of not covering the openings or foramina in the disc so that the air can pass freely through the disc.

In operation a charge of powder is placed on the upper chromium plated surface of the disc and compressed with the air contained within the powder passing freely through the disc to the exterior. After compression the compressed cake can be readily released from the disc by introducing air from an external source through the disc into contact with the compressed cake to release the same from contact with the disc.

The present invention is a simple and inexpensive apparatus for compressing face powder or the like. The device is light in weight and is particularly adapted to be employed on a store counter where face powder can be blended to the customers taste and then compressed into cake form.

The porous metal disc provides a convenient means for discharging and introducing air into the die cavity and eliminates the use of a fabric sheet, such as satin, for releasing purposes. As the use of fabric is eliminated, the material handling and labor involved in compressing a powder cake is substantially reduced.

The drawings illustrate the best mode presently contemplated of carrying out the present invention.

In the drawings:

Figure 1 is a side elevation of the present invention;

Fig. 2 is a top elevation of the apparatus;

Fig. 3 is an enlarged fragmentary section showing the die members before the compressing operation;

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Fig. 4 is a view similar to Fig. 3 showing the die members during the compressing operation; and

Fig. 5 is a top plan view of the lower die member.

The drawings illustrate an apparatus for compressing a finely divided solid material and comprises a base 1 which supports a pair of upstanding columns 2.

A generally cylindrical upper die 3 is supported by the columns 2 by means of a bar 4 which carries the upper die 3 and is removably secured to the upper ends of columns 2. One end of the bar 4 is provided with an opening 5 which receives the upper threaded end of one of the columns and the other end of bar 4 is provided with a recess 6 which receives the upper end of the other of the columns. Nuts 7 are threadedly engaged on :the upper ends of the columns 2 and secure bar 4 in position with respect to the columns. With this construction the opening 5 serves as a pivot and the bar 4 and attached .die 3 can be readily swung or pivoted as desired to permit a charge of powder to be introduced within the apparatus.

The upper die 3 is adapted to be received within .a lower movable die which is composed of an outer member 8 and a central member 9 which is disposed Within the annular recess 10 formed in the inner wall of the member 8. The outer member 8 is provided with a :pair of arms 11 having recesses 12 which receive the respective columns 2 and guide the lower die in movement toward and away from the upper die 3.

To move the lower die relative to the upper die 3 the ram 13 of a hydraulic cylinder 14 is attached to the lower surface of die member 9. Hydraulic fluid from a source of high pressure, not shown, is introduced into the cylinder through conduit 15 and acts against the lower end of ram 13 to movethe lower die upwardly into registry with upper die 3.

The lower die is biased downwardly by a pair of springs 16 which are interconected between pins 17 secured to the outer surface of die member 8 and pins 13 secured to columns 2. The springs 16 serve to urge the lower die downwardly when hydraulic fluid pressure within cylinder 14 is released.

The upper surface of central die member '9 carries a disc 19 which is adapted to support a charge of powder 20 or other finely divided solid material. The disc 19 is formed of a porous or foraminous metal or alloy, such as bronze or stainless steel, and contains a series of minute pores or foramina through which a gaseous fluid, such as air, can pass.

The foraminous metal is produced by conventional powder metallurgy processes in which the powdered metal or alloy is cold formed or sintered to provide the porous or foraminous consistency.

The upper supporting surface of disc 19 is coated by electroplating or the like with a thin layer of chromium 21. The chromium layer has a thickness generally in the range of 0.0005 to 0.003 inch and preferably has a thickness of about 0.001 inch. The use of chromium for the layer 21 enables the pores or openings in the disc '19 to remain open, for the chromium is characterized 'by the property that it will not extend across or cover the openings or pores in the base metal when plated on the same but instead will only cover the surface of the disc extending between the pores. The chromium not only maintains the pores in an open condition but also providcs a smooth supporting surface for the powder which reduces the tendency for the powder to adhere to the surface of the disc during the compressing operation.

The finely divided solid material 20 may be a powder or a material or similar consistency and may take. the form of face powder, to be compressed into a cakeor chemicals, pigments or pharmaceuticals to be compressed into table form or the like.

The powder is compressed within a pan 22 which is provided with a peripheral flange 23. The pan 22 is disposed in an inverted relation on the top of the charge of powder and the powder is compressed therein so that the compressed cake is generally flush with the outer edge of the flange 23. I

To discharge the air contained within the charge of powder 20, the upper surface of the die member 9 is provided with a series of radial grooves 24 and interconnecting circular grooves 25 which provide a network of air passages beneath the disc 19. The radial grooves 24 communicate with a central passage 26 which extends outwardly to the lower surface of die member 9. A conduit 27 is attached by means of a suitable fitting to the passage 26 and provides communication to the atmosphere. A branch conduit 28 establishes communication between conduit 27 and a source of fluid under pressure, not shown. The flow of fluid through conduits 27 and 28 is controlled by valves 29 and 30, respectively.

During the compressing operation, valve 29 is opened so that the conduit 27 is open to the atmosphere, and valve 30 is closed. This permits air entrapped within the powder to pass freely through conduit 27 to the atmosphere. After compression and on release of the compressed cake, valve 29 is closed and valve 30 is opened. Opening of valve 30 introduces a charge of air through conduit 27 and the air passes upwardly through disc 19 against the lower surface of the compressed cake to release the same from engagement with the upper supporting surface 21 of the disc.

The diameter of the disc 19 is of lesser dimension than the internal diameter of the die member 8 to provide an annular clearance 31 between the disc and the die member 8. During compression of the charge of powder, the flange 23 of pan 22 is forced downwardly within the clearance 31. On release of the hydraulic pressure the compressed cake rebounds to a degree so that the outer surface of the finished cake is approximately flush with the edge of the flange 23.

To permit the air entrapped within clearance 31 to escape as the flange 23 of pan 22 is forced therein, the die member 8 is provided with a series of radially extending passages 32 which extend through the walls of the die member 8 and provide communication between clearance 31 and the exterior. During the compressing operation as the flange 23 of the pan 22 moves into the clearance 31 the air within the clearance passes outwardly through passages 32. In addition, any excess powder which may be present will also be discharged through the passages 32.

In operation of the present apparatus the bar 4 is initially pivoted outwardly so that the upper die 3 is out of alignment with the lower die. A charge of powder is then disposed on the upper surface of disc 19 and leveled so that it is substantially flush with the upper surface of die member 8. The pan 22 is then placed on the charge of powder and the upper die 3 swung back into place and locked by threading down nuts 7.

Hydraulic fluid is then introduced into cylinder 14 to raise the lower die and compress the charge of powder between die 3 and disc 19. Air which is entrapped within the powder passes downwardly through the porous disc 19, passages 24 and 25, and conduits 26 and 27 to the exterior.

On release of the pressure the lower die is returned downwardly by springs 16 and a blast of air may then be introduced through conduit 28, conduit 27, passages 24 and 25 to the disc 19. The air passes upwardly through the porous disc and exerts a pressure against the lower surface of the compressed cake to release the same from engagement with the disc.

The present invention provides a novel device for permitting the discharge and introduction of air into a die cavity.

The porous metal disc permits the free passage of air therethrough, but prevents the finely divided solid such as powder from passing through. The use of the porous metal disc provides a substantially increased surface area, through which the air can pass, over that of conventional devices in which the air is released through a series of machined openings. By providing the entire powder sup porting surface as an air conducting medium, the air en trapped within the powder can be rapidly and uniformly discharged from the powder and, conversely, can be introduced uniformly against the entire undersurface of the compressed cake for release of the cake.

The chromium layer 21 provides an extremely smooth surface for the disc which inhibits the adherence of the powder to the disc and yet will not interfere with the porosity of the disc. The cake can be readily freed from engagement with the disc and the use of satin or other fabric on the supporting surface of the die is eliminated. The elimination of the use of fabric reduces the cost of production and substantially reduces the handling and labor involved in the process and thereby decreases the over-all time of operation.

Various modes of carrying out the invention are contemplated as within the'scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. A die member for use in an apparatus for compressing a finely divided solid material comprising, a base portion formed of a generally foraminous metallic substance having a plurality of small openings extending therethrough, and characterized by the ability to permit a gaseous fluid to pass therethrough and to prevent the finely divided solid material from passing therethrough, a thin coating of chromium bonded to a surface of said base portion in position to receive the material to be compressed, said coating of chromium extending only between the openings on said surface of the base portion to permit a gaseous fluid contained within the material to pass freely through the die member to the exterior during compression of said material, and means to pass a separate gaseous fluid under pressure inwardly through said die member and against the surface of the compressed material to release the compressed material from engagement with said coating of chromium and purge the foraminous metallic substance of any divided solid material.

2. A die for use in an apparatus for compressing a finely divided solid material comprising, a support member having a supporting surface and having at least one passage extending from said supporting surface to the exterior of said support member, a forming member having a base portion formed of a porous metallic substance and disposed on said supporting surface of the support member, said porous metallic substance being characterized by the ability to permit a gaseous fluid to pass therethrough and to prevent a finely divided solid material from passing therethrough, said forming member having a thin outer layer of chromium disposed on a surface of the base portion in position to receive the finely divided solid material to be compressed and any gaseous fluid contained within said material being free to pass outwardly through said base portion and said passage to the exterior as said material is compressed into the form of a cake, and means for introducing a separate fluid under pressure into said passage and for passing said fluid through the forming member into contact with said cake to release the cake from engagement with said forming member and purge the porous metallic substance of any divided solid material.

3. An apparatus for compressing a finely divided solid material comprising, a first die member defining a die cavity to receive a charge of finely divided solid material to be compressed and having one end of said die cavity enclosed by a forming member, said forming member having a base portion composed of a porous metallic substance and having a thin inner layer facing said die cavity formed of chromium, said porous substance being characterized by the ability to permit air to pass therethrough and to prevent said material from passing therethrough, a second die member to be received within said die cavity, means to move said die members relative to each other to compress said material into the form of a cake with the air contained within said material passing freely through said forming member to the exterior during the compressing of said material into the form of a cake, and means for passing a fluid under pressure through said forming member into said die cavity and against a surface of said cake to release the cake from engagement with said forming member.

4. An apparatus for compressing a finely divided solid material comprising, a generally cylindrical first die member defining a die cavity to receive a charge of finely divided solid material to be compressed, a forming member disposed within one end of said die cavity and spaced radially inward of said die member to provide an annular clearance therebetween with said clearance being adapted to receive the flange of an inverted container for the material as said material is compressed, said forming member having a base portion composed of a porous metallic substance and having a surface plated with chromium facing said die cavity, said porous substance being characterized by the ability to permit air to pass therethrough and to prevent said material from passing therethrough, a second die member to be received within said die cavity, means to move said die members relative to each other to compress said material into the form of a cake within the container with the air contained within said material passing freely through said forming member to the exterior during the compressing of said material, and port means establishing communication between said clearance and the exterior for exhausting air Within the clearance to the exterior as the flange of said container is received within the clearance.

5. An apparatus for compressing a finely divided solid material comprising, a generally cylindrical first die member defining a die cavity to receive a charge of finely divided solid material to be compressed, a disc disposed within one end of said die cavity and having a slightly smaller external diameter than the internal diameter of said die member, means to axially align said disc with respect to said die member to provide an annular clear ance therebetween with said clearance being adapted to receive the flange of an inverted flanged container for the material as said material is compressed, said disc having a base portion composed of a porous bronze and having a chromium plated surface facing said die cavity, said porous bronze being characterized by the ability to permit air to pass therethrough and to prevent said material from passing therethrough, a second die member to be received wthin said die cavity, means to move said die members relative to each other to compress said material into the form of a cake within the container with the air contained within said material passing freely through said forming member to the exterior during the compressing of said material, and means for passing a fluid under pressure through said forming member into said die cavity and against a surface of said cake to release the compressed cake from engagement with said disc and expel any divided solid material trapped within said porous bronze disc.

6. An apparatus for compressing a finely divided solid material comprising, a generally cylindrical first die member defining a die cavity to receive a charge of finely divided solid material to be compressed, a disc disposed within one end of the die cavity and having a slightly smaller external diameter than the internal diameter of said die member to provide an annular clearance therepressed, and second port means disposed in said first,

die member and communicating with said clearance to permit free escape of the air contained in said clearance as said flange is moved into said clearance during the compressing operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,821,822 Wiegand Sept. 1, 1931 2,026,940 Hendryk Jan. 7, 1936 2,198,612 Hardy Apr. 30, 1940 2,349,920 Welcome May 30, 1944 2,573,141 Heinrich Oct. 30, 1951 OTHER REFERENCES Ziegler et al.: Abstract of application Serial No. 664,668, published Nov. 21, 1950, 640 O.G. 1032. 

